GROWTH OF SI ON THE SI(111) SURFACE

The homoepitaxial growth of Si on a Si(111) surface for T=280-410 degr ees C, and thicknesses up to 210 bilayers has been evaluated using sca nning tunneling microscopy and detailed statistical analyses. In the e arly stages of growth, the formation of and nucleation at antiphase do main boundaries and the formation of metastable crystalline structures become increasingly important at lower temperatures. At larger film t hickness, the height-height correlation functions do not reveal the pr esence of scale-invariant morphologies, Instead, anomalous formation o f pyramidal structures with surrounding denuded zones is observed at t emperatures of 360 degrees C and below. The pyramid size increases wit h increasing temperature and film thickness, but this increase is not consistent with a simple coarsening process. Atomic-scale images indic ate a correlation of these pyramids with the metastable crystalline st ructures observed in growth nuclei at lower coverages. Potential mecha nisms for formation of these anomalous structures and their consequenc es for scale-invariant growth are discussed. Our results indicate that the underlying crystal structure and its associated reconstructions c an play a significant role in determining surface growth morphologies, complicating their long-wavelength dynamic scaling properties.